/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.execution.operator.process;

import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.exception.IntoProcessException;
import org.apache.iotdb.db.mpp.common.header.ColumnHeader;
import org.apache.iotdb.db.mpp.common.header.ColumnHeaderConstant;
import org.apache.iotdb.db.mpp.execution.operator.Operator;
import org.apache.iotdb.db.mpp.execution.operator.OperatorContext;
import org.apache.iotdb.db.mpp.plan.planner.plan.parameter.InputLocation;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;
import org.apache.iotdb.tsfile.read.common.block.TsBlockBuilder;
import org.apache.iotdb.tsfile.read.common.block.column.ColumnBuilder;
import org.apache.iotdb.tsfile.read.common.block.column.TimeColumnBuilder;
import org.apache.iotdb.tsfile.utils.Binary;
import org.apache.iotdb.tsfile.utils.Pair;

import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Collectors;

public class DeviceViewIntoOperator extends AbstractIntoOperator {

  private final Map<String, Map<PartialPath, Map<String, InputLocation>>>
      deviceToTargetPathSourceInputLocationMap;
  private final Map<String, Map<PartialPath, Map<String, TSDataType>>>
      deviceToTargetPathDataTypeMap;
  private final Map<String, Boolean> targetDeviceToAlignedMap;
  private final Map<String, List<Pair<String, PartialPath>>> deviceToSourceTargetPathPairListMap;

  private String currentDevice;

  private final TsBlockBuilder resultTsBlockBuilder;

  public DeviceViewIntoOperator(
      OperatorContext operatorContext,
      Operator child,
      Map<String, Map<PartialPath, Map<String, InputLocation>>>
          deviceToTargetPathSourceInputLocationMap,
      Map<String, Map<PartialPath, Map<String, TSDataType>>> deviceToTargetPathDataTypeMap,
      Map<String, Boolean> targetDeviceToAlignedMap,
      Map<String, List<Pair<String, PartialPath>>> deviceToSourceTargetPathPairListMap,
      Map<String, InputLocation> sourceColumnToInputLocationMap) {
    super(operatorContext, child, null, sourceColumnToInputLocationMap);
    this.deviceToTargetPathSourceInputLocationMap = deviceToTargetPathSourceInputLocationMap;
    this.deviceToTargetPathDataTypeMap = deviceToTargetPathDataTypeMap;
    this.targetDeviceToAlignedMap = targetDeviceToAlignedMap;
    this.deviceToSourceTargetPathPairListMap = deviceToSourceTargetPathPairListMap;

    List<TSDataType> outputDataTypes =
        ColumnHeaderConstant.selectIntoAlignByDeviceColumnHeaders.stream()
            .map(ColumnHeader::getColumnType)
            .collect(Collectors.toList());
    this.resultTsBlockBuilder = new TsBlockBuilder(outputDataTypes);
  }

  @Override
  public TsBlock next() throws IntoProcessException {
    TsBlock inputTsBlock = child.next();
    if (inputTsBlock != null) {
      String device = String.valueOf(inputTsBlock.getValueColumns()[0].getBinary(0));
      if (!Objects.equals(device, currentDevice)) {
        insertMultiTabletsInternally(false);
        updateResultTsBlock();

        insertTabletStatementGenerators = constructInsertTabletStatementGeneratorsByDevice(device);
        currentDevice = device;
      }
      int readIndex = 0;
      while (readIndex < inputTsBlock.getPositionCount()) {
        int lastReadIndex = readIndex;
        for (IntoOperator.InsertTabletStatementGenerator generator :
            insertTabletStatementGenerators) {
          lastReadIndex =
              Math.max(lastReadIndex, generator.processTsBlock(inputTsBlock, readIndex));
        }
        readIndex = lastReadIndex;
        insertMultiTabletsInternally(true);
      }
    }

    if (hasNext()) {
      return null;
    } else {
      insertMultiTabletsInternally(false);
      updateResultTsBlock();
      return resultTsBlockBuilder.build();
    }
  }

  private void updateResultTsBlock() {
    if (currentDevice == null) {
      return;
    }

    TimeColumnBuilder timeColumnBuilder = resultTsBlockBuilder.getTimeColumnBuilder();
    ColumnBuilder[] columnBuilders = resultTsBlockBuilder.getValueColumnBuilders();
    for (Pair<String, PartialPath> sourceTargetPathPair :
        deviceToSourceTargetPathPairListMap.get(currentDevice)) {
      timeColumnBuilder.writeLong(0);
      columnBuilders[0].writeBinary(new Binary(currentDevice));
      columnBuilders[1].writeBinary(new Binary(sourceTargetPathPair.left));
      columnBuilders[2].writeBinary(new Binary(sourceTargetPathPair.right.toString()));
      columnBuilders[3].writeInt(
          findWritten(
              sourceTargetPathPair.right.getDevice(), sourceTargetPathPair.right.getMeasurement()));
      resultTsBlockBuilder.declarePosition();
    }
  }

  private List<IntoOperator.InsertTabletStatementGenerator>
      constructInsertTabletStatementGeneratorsByDevice(String currentDevice) {
    Map<PartialPath, Map<String, InputLocation>> targetPathToSourceInputLocationMap =
        deviceToTargetPathSourceInputLocationMap.get(currentDevice);
    Map<PartialPath, Map<String, TSDataType>> targetPathToDataTypeMap =
        deviceToTargetPathDataTypeMap.get(currentDevice);
    return constructInsertTabletStatementGenerators(
        targetPathToSourceInputLocationMap, targetPathToDataTypeMap, targetDeviceToAlignedMap);
  }
}
